1. Field of the Invention
The present invention pertains to the use of electric motors to operate window coverings systems for draperies, blinds, shades and the like, and specifically to the ability to convert AC-powered motors by means of a plug-in and detachable modular device to DC switching and/or to radio frequency-controlled remote switching.
2. Description of Related Art
Motorized window coverings systems are traditionally driven by AC motors powered by 120V/60 Hz power line supply or in some instances, by 240 V power line supply. In their most simple form they are switched on and off by means of manually operated, hardwired, line voltage switches. In addition there are also low voltage DC motors operating on 12 to 24 Volts DC. These are traditionally switched on and off by means of hardwired DC switches. As a rule, the DC motors are less powerful than the AC motors, and therefore can only handle smaller loads, which translates into smaller sized window coverings.
Roller and lift systems for shades, blinds and the like commonly use tubular motors to power their operation. Such motors are typically mounted inside the rolling mechanism. By contrast, traversing systems (those moving in horizontal or inclined direction) for draperies, vertical blinds and the like commonly use motors which are externally attached to the mechanical parts such as headrails, etc. Those motors are usually configured in a predominantly square or rectangular box-like shape.
Operation of line voltage (AC) motors by means of a connection with a radio or infrared receiver or by means of adding a low voltage switching device has commonly ben accomplished by wire connection with external receiver units. This requires substantial on-site wiring and creates aesthetic problems, especially in interior environments. In addition to wiring problems, such separate, external devices are bulky and expensive as a rule. The modular motor converter invention with its plug-in features can eliminate these disadvantages.
More recently, motors of both types have been developed to incorporate built-in modifiers such as low voltage converters to permit low voltage switching of AC-powered motors. However, by integrating this feature into the motors, it is no longer possible to switch such motors by means of line voltage switching devices. The option of using specific line voltage equipment to switch such low voltage switched motors has effectively been eliminated.
An additional recent development has been the introduction of motors with integrated electronic and radio frequency (RF) switching. Built-in electronic switching is most commonly accomplished by sending electronic signals to the PC board and processor embedded in the motor. Such electronic processors also may be programmed to set the end position stops of the motor. In the alternative, they may be equipped with current-sensing which measures the increased current draw when a drapery or blind is blocked in its movement upon reaching its fully open or closed position. The blockage point is normally reached under full operating speed, thus is also known as the impact stop. Impact stops typically are associated with an increased noise level of operation and, in the case of draperies, with the risk of somewhat inaccurate stacking points due to drapery backflow.